How to brighten a painting to look like the original?

I usually say there are just computer challenges, no computer problems but this summer has been this motto has been harder then usual to keep. Today, I found myself at my art desk, starting a new old project. I thought I’d figured out the solution but it wasn’t working either.

Then I broke out my computer to see if I could figure out how to brighten a photo of a painting I took so it would look bright like the original painting when I printed my notecards. I think I might have brightened it up a little but I still feel like the greens are just too dark and not like the bright lime greens of the original painting.

I also can’t seem to figure out how to make my jpegs rotate in wordpress. Even if I rotate the image in iPhoto or Preview, when I upload it to wordpress it still shows up vertical instead of horizontal.